I. Introduction
At present, the KT6368A Bluetooth chip requires a crystal oscillator to be equipped. The parameters are 24MHZ, the load capacitance is 12pF, and the accuracy is 10ppM. In fact, the manufacturers of crystal oscillators generally control it within ± 8ppM.
The unit ppM is very small. 1ppM is equal to 0.0001 percent. ppM stands for parts per million or a few parts per million.
That is 10ppM. For a 24MHZ crystal oscillator, it is ± 240HZ, and the precision is extremely high.
The KT6368A needs to operate in the best condition, that is, the crystal oscillator is 24M, then the frequency is doubled to 2.4GHZ, and the error is controlled within ± 30KHZ, which is very comfortable.
So the crystal oscillators we supply are basically much higher than this parameter. They can be used directly without the need for the unnecessary action of calibrating the frequency offset.
It is essential to note that the load capacitor of the crystal oscillator does not need to be soldered; otherwise, it will have the opposite effect.
II. Detailed Explanation
2.1 Hardware Specifications
2.2 Test Instructions for Crystal Oscillator M49 Packaging
The KT6368A chip was tested. The crystal oscillator used is the commonly used M49 model [as shown in the above picture], and the testing tool is the Bluetooth test kit [as shown on the right above picture].
Five chips were randomly tested, and most of them were around "± 20K".
2.3 Test Instructions for the 3225 package of the crystal oscillator
The KT6368A chip was tested. The crystal oscillator uses the commonly used 3225 package [as shown in the upper left picture], and the testing tool is a Bluetooth test kit [as shown in the upper right picture].
Five chips were randomly tested, and most of them were around "± 10K".
III. Summary
If the cost allows, it is recommended to use the 3225 package, which is more stable. Of course, the cost is slightly higher, about 5 cents.
If the cost requirement is relatively high, using the M49 package is also fine.
IV. Other instructions
The KT6368A was tested.
The crystal oscillator used is the commonly used M49 model, and the testing tool is a Bluetooth test kit.
- The first situation is that the chip uses a socket
👉 The frequency offset of KT6368A was basically maintained at around "-55K", and five chips were tested.
👉 The frequency offset of KT6328A was basically maintained at around "-60K", and three chips were tested.
- The second situation is that the chip is directly soldered onto the board.
" The frequency offset of KT6368A is basically within "-25K".
" The frequency offset of KT6328A is basically around "-30K".
The conclusion is that the common model of M49 crystal oscillator has no problem. It's just that the chip is directly soldered onto the board, and the test results are also fine.
However, if the chip uses a socket, the frequency offset is around "-60K", which is unacceptable.
By inquiring with the supplier, the parameters of the M49 and 3225 they supply are the same; it's just that the packaging is different.
Meanwhile. The 3225 crystal oscillator performs very well, basically within the range of "± 10K". Therefore, if you need good performance, it is better to use the 3225.
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